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On 2017-08-25 16:33, David C wrote:
> It will be my birthday soon and when I am asked what I want I may say "a 
reconditioned A12 from Celestaire".
> But I have a problem. I live in an area with light pollution.

I found the A12 difficult (but not impossible) to use for star shots in
a light polluted area, due to the bubble illumination system. It shows
the bubble as a dark circle against a lighted background. However, the
latter also washes out the star.

Another problem is batteries. Apparently dry cells in the 1940s were a
little smaller in diameter. I had to laboriously strip the jackets from
modern batteries to get them to fit.

The viewing position for star shots is not the best, as you must hold
the sextant above eye level and look up through it. On the other hand,
the A12 is comfortable for sun shots since it's held at chest height and
you gaze down into it.

I still have the A12, as well as a periscopic bubble sextant. But I
haven't used either in several years. A marine sextant (sans artificial
horizon) is much more fun.

   

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